1. Field of the Invention
The present invention relates to a reflective liquid crystal display device having superior reliability.
2. Description of the Related Art
In recent years, reflective liquid crystal display devices having advantages in reduction of power consumption and thickness have been widely used as display devices for portable data terminals and handy type personal computers.
Hitherto, as the aforementioned reflective liquid crystal display device, an external reflective plate type display device, in which a reflective plate is provided on the outside of one substrate of a pair of substrates opposing to each other with a liquid crystal layer therebetween, has been known. However, regarding this reflective liquid crystal display device having the external reflective plate, there is a problem in that since a light incident from outside reaches the reflective plate through two substrates, display is likely to be darkened.
In order to reduce the number of substrates through which the light incident from outside reaches the reflective plate, a reflective liquid crystal display device, in which a reflective film is formed on one surface of one substrate of the aforementioned substrate pair, and this reflective film is included between the substrate pair, has been known.
However, regarding the aforementioned reflective liquid crystal display device having the built-in type reflective film, when the surface of the reflective film is mirror-finished, there has been a problem of reduction in contrast due to a reflected light which intensely occurs at a specified angle.
In order to solve the aforementioned problems, as shown in FIG. 6, a display device corresponding to the aforementioned reflective liquid crystal display device including a built-in reflective metal film with a surface having an uneven shape has been suggested.
FIG. 6 is a partial sectional structure diagram of the end portion of the aforementioned reflective liquid crystal display device.
In FIG. 6, a reflective liquid crystal display device 100 has a configuration in which a first substrate 110 and a second substrate 120 are opposed to each other, and a liquid crystal layer 130 is enclosed therebetween with a seal member 140.
On the liquid crystal layer 130 side of the first substrate 110, an organic film 111 provided with many bumps and dips, a reflective metal film 112, an overcoat film 114, a first electrode layer 115, and a first orientation film 116 are formed in order by lamination. On the liquid crystal layer side of the second substrate 120, second electrode layers 125, an overcoat film 126, and a second orientation film 127 are formed in order by lamination.
On the surface of opposite side of the liquid crystal layer 130 side of the second substrate 120, a phase difference plate 128 and a polarizing plate 129 are provided.
In the aforementioned reflective liquid crystal display device 100, since the reflective metal film 112 is built-in between the first substrate 110 and the second substrate 120, a light incident from the second substrate 120 side reaches the reflective metal film 112 through only the second substrate 120, and a reflected light returns to the outside of the second substrate 120 through only the second substrate as well. AS a consequence, loss of the light during passing through substrates can be reduced so as to achieve well-lighted display.
Since the reflective metal film 112 is formed on the organic film 111 with a surface having a shape of bumps and dips, the reflected light from the reflective metal film 112 is scattered, so that contrast and viewing angle property are improved.
Therefore, regarding the reflective liquid crystal display device 100 having the aforementioned configuration, well-lighted display and wide viewing angle can be achieved.
However, in the conventional reflective liquid crystal display device 100 having the aforementioned configuration, since the organic film 111 is formed so as to reach the outer end of the substrate 110, as shown in FIG. 6, the outer end face 111a of the organic film 111 contacts with the outside air.
This organic film 111 is composed of an ultraviolet curing acrylic resin, etc., and is likely to be degraded due to absorption of moisture. Consequently, when the outer end face 111a of the organic film 111 contacts with the outside air in a manner similar to that in the aforementioned reflective liquid crystal display device 100, the organic film 111 may be degraded due to absorption of moisture from the outer end face 111a, and the organic film 111 may peel off from the first substrate 110 or from the overcoat film 114, because moisture permeates into the joint end 110a of the organic film 111 and the first substrate 110, or into the joint end 114a of the organic film 111 and the overcoat film 114.